[PATCH v2 1/5] cxl/mem: Introduce cxl_decode_register_block()

From: ira . weiny
Date: Fri May 21 2021 - 20:12:16 EST


From: Ira Weiny <ira.weiny@xxxxxxxxx>

Each register block located in the DVSEC needs to be decoded from 2
words, 'register offset high' and 'register offset low'.

Create a function, cxl_decode_register_block() to perform this decode
and return the bar, offset, and register type of the register block.

Then use the values decoded in cxl_mem_map_regblock() instead of passing
the raw registers.

Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>

---
Changes for V2:
Push this to the start of the series
---
drivers/cxl/pci.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 8bdae74d7d78..b2f978954daa 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -922,17 +922,13 @@ static struct cxl_mem *cxl_mem_create(struct pci_dev *pdev)
return cxlm;
}

-static void __iomem *cxl_mem_map_regblock(struct cxl_mem *cxlm, u32 reg_lo, u32 reg_hi)
+static void __iomem *cxl_mem_map_regblock(struct cxl_mem *cxlm,
+ u8 bar, u64 offset)
{
struct pci_dev *pdev = cxlm->pdev;
struct device *dev = &pdev->dev;
- u64 offset;
- u8 bar;
int rc;

- offset = ((u64)reg_hi << 32) | (reg_lo & CXL_REGLOC_ADDR_MASK);
- bar = FIELD_GET(CXL_REGLOC_BIR_MASK, reg_lo);
-
/* Basic sanity check that BAR is big enough */
if (pci_resource_len(pdev, bar) < offset) {
dev_err(dev, "BAR%d: %pr: too small (offset: %#llx)\n", bar,
@@ -974,6 +970,14 @@ static int cxl_mem_dvsec(struct pci_dev *pdev, int dvsec)
return 0;
}

+static void cxl_decode_register_block(u32 reg_lo, u32 reg_hi,
+ u8 *bar, u64 *offset, u8 *reg_type)
+{
+ *offset = ((u64)reg_hi << 32) | (reg_lo & CXL_REGLOC_ADDR_MASK);
+ *bar = FIELD_GET(CXL_REGLOC_BIR_MASK, reg_lo);
+ *reg_type = FIELD_GET(CXL_REGLOC_RBI_MASK, reg_lo);
+}
+
/**
* cxl_mem_setup_regs() - Setup necessary MMIO.
* @cxlm: The CXL memory device to communicate with.
@@ -1009,15 +1013,21 @@ static int cxl_mem_setup_regs(struct cxl_mem *cxlm)
for (i = 0; i < regblocks; i++, regloc += 8) {
u32 reg_lo, reg_hi;
u8 reg_type;
+ u64 offset;
+ u8 bar;

/* "register low and high" contain other bits */
pci_read_config_dword(pdev, regloc, &reg_lo);
pci_read_config_dword(pdev, regloc + 4, &reg_hi);

- reg_type = FIELD_GET(CXL_REGLOC_RBI_MASK, reg_lo);
+ cxl_decode_register_block(reg_lo, reg_hi, &bar, &offset,
+ &reg_type);
+
+ dev_dbg(dev, "Found register block in bar %u @ 0x%llx of type %u\n",
+ bar, offset, reg_type);

if (reg_type == CXL_REGLOC_RBI_MEMDEV) {
- base = cxl_mem_map_regblock(cxlm, reg_lo, reg_hi);
+ base = cxl_mem_map_regblock(cxlm, bar, offset);
if (IS_ERR(base))
return PTR_ERR(base);
break;
--
2.28.0.rc0.12.gb6a658bd00c9